Method of producing tarnish-resisting silver and silver plate



Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

, DANIEL GRAY AND RIcIIARD o. BAILEY, or ONEIDA, AND- ILLIAM s. MURRA or UTIGA, NEW YORK, ASSIGNORS TO ONEIDA COMMUNITY, LIMITED, or ONEIDA, .NEW YORK, A CORPORATION on NEW YORK.

l METHOD OI PRODUCING TARNISH-RESISTING SILVER AND SILVER PLATE.

No Drawing. Application filed November 5, 1923,

This invention relates to a process for producing tarnish-resisting silver and silver plate. c

,The tarnishing of silverware or silver plated .ware, on the shelves of the dealer, and in ;a house or other place of use, is a source of much inconvenience and expense in that frequent cleaning of the articles, by rubbing, polishing, etc. is necessary to restore them to their natural color and brightness, such cleaning also in time resulting in more or less wear of the polished surface and its surface ornamentation.

It is the object of the present invention to provide a process which will render such silver and silver plated ware tarnish resisting and to thus overcome these objec tions.

This is accomplished according to the present invention by combining with the silver or silver plate a metal or metals which, in such combination, will have a shielding action as to tarnish so that the article as a Whole will be tarnish resisting.

The metal preferred for this purpose is mercury.

The present invention has particular reference to the production of silver or silver plate of substantially pure silver except for the presence in it of the mercury, or silver or silver plate having the silver-content of coin or sterling silver, namely about 90% or 92%%', the other content being a base metal, such as copper, and mercury.

According to the present invention this tarnish resisting silverand plate are-preferably produced by the use of mercury, as before stated, and the exposure of the silver or silver plate to the vapor of the mercury in a low temperature furnace of the closed mufile type.

Preferably the silver or silver plate is taken in an unfinished state, so far as the burnishing, polishing, etc. of its surface is concerned, as in such state it absorbs the mercury more quickly than it would if its surface were finished.

Stated more indetail, the silver or silver plate, preferabl in its unfinished state and the mercury w ich is to combine with it Serial No. 673,028. Renewed September 27, 1928.

mercury free from any agentsthat wouldinterfere with the absorption of the mercury by the silver or silver plate.

Good results are obtainable by the use of 10 parts by weight of mercury to 90 parts by weight of silver or silver plate, but a lower percentage or quantity of mercury is preferable, as for example, 2 parts by weight of mercury to 98 parts by weight of the silver or silver plate. By weight of the silver plate is meant, the weight of the silver plate or plating itself, and does not include the weight of the base on which it is plated.

What is claimed is:-

1. The herein described processes of producing tarnish resisting silver or silver plate which consist in vaporizing mercury and exposing the silver or silver plate to such vapor in an atmsophere free of oxygen and other agents which would interfere with the absorption of the mercury by the silver or silver plate.

2. The herein described processes of producing tarnish resisting silver or silver plate having a silver content of about 90% or more, which consists in vaporizing mercury and exposing the silver or silver plate to such vapor in an atmosphere free of oxygen or other agents which would interfere with the absorption of the mercury by the silver or silverplate, the mercury so vaporized and absorbed constituting not more than 10% of the finished product.

In testimony whereof, we have hereunto set our hands.

DANIEL GRAY. RICHARD o. BAILEY. j ILLIA s. U RA 

